real estate was highly leveraged borrowing that took national household debt and repayment figures to new records. Facebook stock is being bought by institutions and funds, and those numbers still don't come close to 98/99 records despite online revenue being an order of magnitude larger today than what it was then
This is no different than the real estate cycle in L.A. or South Florida a few years ago, when people would buy and sell condos based on market potential multiple times before the condo was even finished. It all works until someone down the line tries to cash in. It will work for FaceBook and Goldman Sachs, but a whole lot of consumer investors are going to get AOL'd in the long run.